Wavefront shaping with a Hadamard basis for scattering soil imaging

Area of Science:

• Optics
• Soil Science
• Microbiology

Background:

• Soil's complex, scattering nature hinders optical imaging of vital plant-microbial-mineral interactions.
• Effective imaging is crucial for understanding plant health and soil carbon sequestration processes.

Purpose of the Study:

• To develop an advanced wavefront shaping method for focusing light through scattering soil media.
• To overcome limitations in optical imaging caused by scattering and low contrast in soil.

Main Methods:

• Utilized adaptive stochastic parallel gradient descent optimization with a Hadamard basis for wavefront shaping.
• Implemented a sparse representation of the wavefront with reduced dimensionality.
• Optimized subsets of the Hadamard basis sequentially for improved efficiency.

Main Results:

• Demonstrated a significantly higher convergence rate (approximately seven times faster) compared to optimizing all pixels simultaneously.
• Achieved superior overall performance in focusing light through soil mineral samples.
• Validated the method through both simulation and experimental optimization.

Conclusions:

• The developed wavefront shaping method effectively overcomes light scattering in soil, enabling clearer imaging.
• This approach offers a substantial improvement in optimization speed and performance for complex optical systems.
• The technique has broad applicability to other high-dimensional optimization challenges in adaptive optics and wavefront shaping.